The http: component provides HTTP based endpoints for consuming external HTTP resources (as a client to call external servers using HTTP).

http:hostname[:port][/resourceUri][?options]

Will default use port 80 for http and 443 for https.

	camel-http vs camel-jetty
	You can only produce to endpoints generated by the HTTP component. Therefore it should never be used as input into your Routes. To bind/expose an HTTP endpoint via a http server as input to a route, you can use the Jetty Component

FUSE Mediation Router will store the http response from the external server on the OUT body. All headers from the IN message will be copied to the OUT message so headers is preserved during routing. Additionally FUSE Mediation Router will add the http response headers as well to the OUT message.

FUSE Mediation Router will handle according to the http response code:

	throwExceptionOnFailure
	The option throwExceptionOnFailure can be set to false to prevent the HttpOperationFailedException to be thrown for failed response codes. This allows you to get any response from the remote server. There is a sample below demonstrating this.

This exception contains the following information

In FUSE Mediation Router 1.5 the following algorithm is used to determine if either GET or POST http method should be used: 1. Use method provided in header 2. GET is query string is provided in header 3. GET if endpoint is configured with a query string 4. POST if there is data to send (body is not null) 5. GET otherwise

You can set the http producer's URI directly form the endpoint URI. In the route below FUSE Mediation Router will call our to the external server oldhost using HTTP.

        from("direct:start")
	    .to("http://oldhost");

And the equivalent spring sample:

<camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
  <route>
    <from uri="direct:start"/>
    <to uri="http://oldhost"/>
  </route>
</camelContext>

In FUSE Mediation Router 1.5.1 you can override the http endpoint URI by adding a header with the key HttpProducer.HTTP_URI on the message.

        from("direct:start")
            .setHeader(org.apache.camel.component.http.HttpProducer.HTTP_URI, constant("http://newhost"))
	    .to("http://oldhost");

In the sample above FUSE Mediation Router will call the http://newhost despite the endpoint is configured with http://oldhost.

And the same code in FUSE Mediation Router 2.0:

        from("direct:start")
            .setHeader(HttpConstants.HTTP_URI, constant("http://newhost"))
	    .to("http://oldhost");

Where Constants is the class org.apache.camel.component.http.Constants.

The http producer supports URI parameters to be sent to the HTTP server. The URI parameters can either be set directly on the endpoint URI or as a header with the key HttpProducer.QUERY on the message.

        from("direct:start")
	    .to("http://oldhost?order=123&detail=short");

Or options provided in a header:

        from("direct:start")
            .setHeader(HttpConstants.HTTP_QUERY, constant("order=123&detail=short"))
	    .to("http://oldhost");

The HTTP component provides a way to set the HTTP request method by setting the message header. Here is an example;

        from("direct:start")
            .setHeader(HttpConstants.HTTP_METHOD, constant(org.apache.camel.component.http.HttpMethods.POST))
	    .to("http://www.google.com")
            .to("mock:results");   

The method can be written a bit shorter using the string constants:

            .setHeader("CamelHttpMethod", constant("POST"))

And the equivalent spring sample:

<camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
  <route>
    <from uri="direct:start"/>
    <setHeader headerName="CamelHttpMethod">
        <constant>POST</constant>
    </setHeader>
    <to uri="http://www.google.com"/>
    <to uri="mock:results"/>
  </route>
</camelContext>

If you are using POST to send data you can configure the charset using the Exchange property:

   exchange.setProperty(Exchange.CHARSET_NAME, "iso-8859-1");

Or the HttpClient options: httpClient.contentCharset=iso-8859-1

The sample polls the Google homepage every 10 seconds and write the page to the file message.html

from("timer://foo?fixedRate=true&delay=0&period=10000")
    .to("http://www.google.com")
    .setHeader(FileComponent.HEADER_FILE_NAME, "message.html").to("file:target/google");

In this sample we have the complete URI endpoint that is just what you would have typed in a web browser. Multiple URI parameters can of course be set using the & as separator, just as you would in the web browser. FUSE Mediation Router does no tricks here.

// we query for Camel at the Google page
template.sendBody("http://www.google.com/search?q=Camel", null);

Map headers = new HashMap();
headers.put(HttpProducer.QUERY, "q=Camel&lr=lang_en");
// we query for Camel and English language at Google
template.sendBody("http://www.google.com/search", null, headers);

In the header value above notice that it should not be prefixed with ? and you can separate parameters as usual with the & char.

You can get the http response code from the http component by getting the value from out message header with HttpProducer.HTTP_RESPONSE_CODE.

   Exchange exchange = template.send("http://www.google.com/search", new Processor() {
            public void process(Exchange exchange) throws Exception {
                exchange.getIn().setHeader(HttpProducer.QUERY, constant("hl=en&q=activemq"));
            }
   });
   Message out = exchange.getOut();
   int responseCode = out.getHeader(HttpProducer.HTTP_RESPONSE_CODE, Integer.class);

Available as of FUSE Mediation Router 2.0 In the route below we want to route a message that we enrich with data returned from a remote HTTP call. As we want any response from the remote server we set the throwExceptionOnFailure option to false so we get any response in the AggregationStrategy. As the code is based on an unit test that simulates a http status code 404, there is some assertion code etc.

// We set throwExceptionOnFailure to false to let Camel return any response from the remove HTTP server without thrown
// HttpOperationFailedException in case of failures.
// This allows us to handle all responses in the aggregation strategy where we can check the HTTP response code
// and decide what to do. As this is based on an unit test we assert the code is 404
from("direct:start").enrich("http://localhost:8222/myserver?throwExceptionOnFailure=false&user=Camel", new AggregationStrategy() {
    public Exchange aggregate(Exchange original, Exchange resource) {
        // get the response code
        Integer code = resource.getOut().getHeader(Exchange.HTTP_RESPONSE_CODE, Integer.class);
        assertEquals(404, code.intValue());
        return resource;
    }
}).to("mock:result");

// this is our jetty server where we simulate the 404
from("jetty://http://localhost:8222/myserver")
        .process(new Processor() {
            public void process(Exchange exchange) throws Exception {
                exchange.getOut().setBody("Page not found");
                exchange.getOut().setHeader(Exchange.HTTP_RESPONSE_CODE, 404);
            }
        });

If you need more control over the http producer you should use the HttpComponent where you can set various classes to give you custom behavior.

The Http Component have a org.apache.commons.httpclient.HttpConnectionManager where you can configure various global configuration for the given component. By global, we mean, that any endpoint the component creates has the same shared HttpConnectionManager. So if we want to set a different value for the max connection per host, we need to define on the http component and not on the endpoint URI that we usually uses. So here comes:

First we define the http component in spring XML. Yes we can use the same scheme name http that FUSE Mediation Router otherwise will auto discover and create the component with default settings. What we need is to overrule this so we can set our options. In the sample below we set the max connection to 5 instead of the default of 2.

<bean id="http" class="org.apache.camel.component.http.HttpComponent">
    <property name="camelContext" ref="camel"/>
    <property name="httpConnectionManager" ref="myHttpConnectionManager"/>
</bean>

<bean id="myHttpConnectionManager" class="org.apache.commons.httpclient.MultiThreadedHttpConnectionManager">
    <property name="params" ref="myHttpConnectionManagerParams"/>
</bean>

<bean id="myHttpConnectionManagerParams" class="org.apache.commons.httpclient.params.HttpConnectionManagerParams">
    <property name="defaultMaxConnectionsPerHost" value="5"/>
</bean>

And then we can just use it as we normally do in our routes:

<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring" trace="true">
    <route>
        <from uri="direct:start"/>
        <to uri="http://www.google.com"/>
        <to uri="mock:result"/>
    </route>
</camelContext>